Eryngium planum 'Blaukappe'
An oldie but a goodie. Deep blue ageing to purple thistle-like flowers are borne in profusion from late spring into early summer. Trim spent flowers to encourage further blooms, although subsequent flushes aren't as tall as the first flush. Nevertheless it is an enjoyable extension to the show. Mounding basal foliage to 0.25mH and 0.35mW. Flowers up to 0.75mH. Full sun to part shade.